1. Field of the Invention
The present invention relates to an improved agitator structure, having flexible vanes and slide bars, that enhances clothes washability while minimizing fabric abrasion and vane breakage.
2. Description of the Related Art
The general construction of clothes washers is well known in the art. A common type of clothes washing machine is the vertical axis washer having an agitator and incorporating a submersion process. An imperforate tub is mounted in a perforated wash basket for receiving clothing and the tub is filled with a wash liquid of detergent and water. An oscillating or unidirectional agitator is positioned within the wash basket and imparts mechanical energy to the submerged clothing.
Many agitators have fins, or vanes, extending radially from the bottom portion of the agitator, just above the wash plate, similar to those described in U.S. Pat. No. 5,651,278 (Pinkowski) and U.S. Pat. No. 4,555,919 (Brenner et al.), assigned to the assignee of the present application, the disclosure of which is incorporated by reference herein. The vanes help push the clothes in a circular direction around the center agitator post, or barrel, and impart mechanical energy to the swirling wash liquid. As will be appreciated, there must be a balance between the strength and the flexibility of the vanes because it is desired to have vanes that do not break but also ones that reduce fabric abrasion.
Stress is exerted on vanes as they circulate water and push clothes in a circular direction. The vanes must flex in multiple directions to absorb the stress caused by circulating water and moving clothes without breaking off during the wash process. One method employed to provide flexibility is the use of a tapered vane where the vane has a thicker cross-section at the juncture with the center barrel portion of the agitator and a gradually thinner cross-section as it tapers toward the tip. It is also known to provide a vane that has not just one planar surface on each side, but multiple planar surfaces on each side. A popular agitator used today employs three planar surfaces on each side as the vane transitions from the center post to the tip. For the same stress, the use of three planes allows more deflection at the vane tip than the one plane, tapered vane. However, there is still stress exerted on the vane, especially in a twisting fashion, and it is desired to have the greatest deflection possible for a given amount of stress.
Additionally, it is necessary to have clothes turn over as the agitator rotates them so they do not get stuck next to the center barrel of the agitator. Therefore, many agitators in the prior art slope gradually from the center barrel to the skirt area to provide a means for rolling clothes outward. However, this construction requires a vane to be mounted above the slope so it is provided on the center barrel at a great vertical distance from the skirt, resulting in the mounted area of the vane absorbing a lot of the load. The loading in the bottom of the vane, below the connection point of the vane, is absorbed at the bottom connection point. Therefore, it would be an improvement to provide an agitator construction with a vane mounted closer to the skirt, thus lowering the bottom connection point of the vane, resulting in higher deflection for the same stress level.
The ability of a vane to absorb stress is also dependent upon the thickness of the vane. If other means of reducing stress, besides varying the thickness of the vane, can be achieved, then the thickness of the vane can be reduced. This increases flexibility of the vane. Often, to provide reliability against breakage, vanes are at least 2 mm thick.
For clothes washers having an agitator with vanes, it is desirable to have vanes that have superior tip deflection and slides between the vanes for rolling clothes outward, thus enhancing washability while minimizing vane breakage.